A rectifier circuit is used to convert an AC power signal to a DC power signal. A traditional rectifier circuit is a half-bridge or a full-bridge rectifier circuit that uses diodes. In a positive half-cycle of an AC power, a current flows from an input terminal of a rectifier circuit to an output terminal of the rectifier circuit through different paths as determined by diodes, so that a directional DC current is obtained at the output terminal. The rectifier circuit with diodes takes advantages of a relatively simple structure and low product costs, but still may have relatively low power efficiency because of the large losses consumed by the diodes.